At present, in the aeronautical, nuclear and oil industry, the preservation of the mechanical integrity in its mobile and stationary installations is being considered as part of its operational and safety policies, through maintenance and inspection actions, which in its most are made with the components operating, without programmed shutdowns of the plant, especially in the case of inspection.
In the case of the petroleum industry, by means of non-destructive test inspection provides information on discontinuities and defects in static components, such as pressure vessels and pipelines in service, information necessary to determine the structural condition of said components and their remaining life time, which helps to prevent potential problems and to make relevant decisions for repairs or maintenance, actions necessary to preserve the structural integrity and thus the safety of the facilities. Particularly in the processing facilities in the marine oil platforms there is a large number of pipes, which require periodic inspection to evaluate their mechanical integrity and increase the reliability and safety of their functionality, with the particularity that they are installed inside plants at sea, in confined spaces at different levels, even “flown” away from the main structure of the platform, which makes it difficult to inspect, making it necessary to use at least structures of tubular scaffolds, hanging scaffolds and ladders in order to be in direct contact with the pipe, however, the handling and safe installation of these scaffolds is a process that requires a significant investment of additional time to the inspection activities of considerably large extensions of pipelines, this logistical process includes the handling of this tool In the facilities of the plant, as well as its installation in each point where inaccessible pipe is found, turns out to be in many cases a limitation for the complete inspection of the plant.
In order to provide a solution to the aforementioned limitations, Antonio Ramirez Martinez, in patent application publication MXPA04012770, describes equipment which is capable of adhering to and moving through the ferromagnetic structures, either horizontally or vertically, with The purpose of measuring the wall thicknesses of said metal structures in an autonomous and robotic manner, or remotely controlled, using ultrasound as a means of measuring the thickness; The inspection equipment is constituted by a) a system of adherence; B) a traction system; C) a suspension system; D) a positioning system of the transducer of ultrasonic; E) a control system; (F) a remote control system; G) a data recording system; H) a verticality tracking system; And i) software.
Also Hayata Takashi and Nakahara Hirotaka describe in patent publication JP8338831, a surface inspection device, which is light and small to be stably executed even on a curved surface, constituted by at least one pair of magnetic wheels which are attracted towards the wall surface, are provided by vehicle on the right and left side thereof; An engine and a reduction mechanism that moves the wheels that are supported to the body with suspension mechanisms; A test ultrasonic, which is attached to the central section of the body via a spring. When the same rotation is applied to all the wheels, the body moves in a circumferential direction in a pipe and when different rotations are applied to the wheels 10a, 10b and to the wheels 10c, 10d respectively, the body is controlled for moved in spiral over the pipe.
While the curvature of the face varies, the controlled of each of the wheels 10a-10d, of each of the motors and of each reduction mechanism may correspond to the variation of the curvature thus until reaching stability.
Xinjun Wu, Jianming Yuan, Chen Huang, Baijiang An and Yihua Kang in the Chinese patent CN101138994, describe a trailing robot for pipes with magnetic wheels for a vehicle, which includes four wheels, a permanent magnetic absorption mechanism and a mechanism of direction. The vehicle is made up of four wheels, which are installed in the frame of the vehicle. The set of wheels include a wheel frame, a wheel, a wheel handle, a handle steering, a speed reducer and an engine.
The mechanism of permanent magnetic absorption includes a small jaw and two magnets with inverted polarity. The steering mechanism includes a bracket, a chain drive wheel, a chain wheel drive shaft, a chain, a speed reducer and the engine. The permanent magnetic absorption mechanism is connected to the underside of the vehicle frame. The steering mechanism is fixed to the frame of the vehicle. The robot of the this document can trace on the outer surface of the pipe in an oblique pipe agreed on any route and can reach any external position of the pipe surface according to the requirements.
Also known from the state of the art is the document MX2010007204 (Magallanes), which discloses an apparatus for external inspection of pipes formed by a magnetic traction arrangement in its lower part and at least one inspection device mounted on the body, Magnetic drive comprises two magnetic wheels formed by a circular magnet, a toothed cap on its circumference disposed adjacent the magnet and a cap with at least a pair of notches on its circumference positioned on the opposite face of the magnet, this apparatus includes a Ultrasonic thickness measurement device, a video camera, a servomotor coupled to each wheel, these servo motors controlled by a software.
The solutions described by the patent documents offer an inspection vehicle for pipes with magnetic wheels of certain adhesion characteristics that allow it to adapt to the curvature of the surface for different situations, however, the metallic character with a smooth surface of the Wheels causes the coefficient of friction with respect to the surface to be inspected also metallic on the one to be displaced is minimal, also generate problems of displacement of the vehicle concretely when this one is with weldings or any other type of irregularities that usually exist in the walls of the pipeline or of the element on which the vehicle is to move, losing adhesion and preventing its movement, also none of the vehicles of the state of the art provides a complete control and stability in the advancement of the wheels allowing not only the advance front and back but also a controlled rotation.
In view of the foregoing, it is therefore necessary to provide a compact, lightweight, small-sized external pipe inspection apparatus which allows for the external inspection of complex arrangement pipes, with corrosion obstacles, welds or any other irregularities and Of small thicknesses of 101.6 mm in diameter (4 inches in diameter), where the magnetic wheels have a better adhesion for pipes of this type and that allow their translational and rotational displacement through these irregularities, conserving the force of adhesion and power Thus passing these obstacles. As well as performing the function of transporting external inspection devices such as video cameras, ultrasonic, laser sensors, etc. The present invention can be widely used for the maintenance, cleaning, and inspection work of the storage tanks.